Siemens Sitrans LR250, Руководство по эксплуатации, Страница: 178 / 306

Diagnosing and troubleshooting
10.4 Operation troubleshooting
SITRANS LR250 (PROFIBUS PA)
176
Operating Instructions, 08/2014, A5E32221386-AC
10.4 Operation troubleshooting
Operating symptoms, probable causes, and resolutions.
Symptom Cause Action
Display shows level or target is out of range
•
check specifications
• check Low Calibration Pt. (1.6.)
•
increase Confidence (2.5.9.1.)
Display shows material build-up on antenna
•
clean the antenna
• re-locate SITRANS LR250
Display shows location or aiming:
• poor installation
•
flange not level
• Auto False Echo Suppression
may be incorrectly applied
• check to ensure nozzle is vertical
•
ensure end of antenna protrudes from end of nozzle
• review Auto False Echo Suppression (Page 236)
•
ensure Auto False Echo Suppression Range is set
correctly
Display shows antenna malfunction:
•
temperature too high
•
physical damage
•
excessive foam
•
multiple echoes
•
check temperature in Maximum Value (3.3.2.)
• use foam deflector or stillpipe
•
relocate
• use a defoamer
•
set Algorithm (2.5.7.1.) to tF (trueFirst echo)
Reading does not
change, but the level
does
SITRANS LR250 processing
wrong echo, for example, vessel
wall, or structural member
• re-locate SITRANS LR250
•
check nozzle for internal burrs or welds
• rotate device 90°
•
use Auto False Echo Suppression (2.5.10.1.)
• if necessary: see Auto False Echo Suppression
(Page 236)
Measurement is
consistently off by a
constant amount
• setting for Low Calibration
Point (2.3.7.1.) not correct
•
setting for Sensor Offset
(2.3.7.3.) not correct
• check distance from sensor reference point to Low
Calibration Point (2.3.7.1.)
•
check Sensor Offset (2.3.7.3.)
Screen blank power error
• check nameplate rating against voltage supply
•
check power wiring or source
too much load resistance
•
change barrier type, or
•
remove something from the loop, or
•
increase supply voltage
• reduce wire distance or use larger gage wire